The state Department of Transportation now says the tunnel-boring machine, which the state initially said might start up again in September, won't get back to work until March 2015.

The Washington State Department of Transportation today officially acknowledged that the opening of the downtown deep-bore tunnel will be delayed by at least a year from the contractor's original target date of late 2015.

That's assuming that a 16-month delay in tunneling can be offset by a four-month increase in efficiency, which tunnel engineers say will be accomplished by operating around the clock instead of just during normal business hours. (They're building a noise wall to minimize the impact on Pioneer Square businesses and residents.)

In February, tunnel engineers and WSDOT officials announced that under an "optimistic" scenario, the tunnel-boring machine would be back up and running by this coming September.

Image of tunnel segments via WSDOT on Flickr.

The tunnel-boring machine, known as "Bertha," has been stalled since December of last year, when damage to the seals surrounding the bearing that drives its cutterhead caused it to overheat. Seattle Tunnel Partners, the group of firms responsible for digging the tunnel, is digging a giant pit in front of the machine that will be encased by concrete pilings; Bertha will then dig its way into the pit through the pilings, and STP will remove the cutterhead to repair the seals (and potentially the bearings; because the machine is underground, engineers don't know yet whether the bearings themselves are damaged).

In a rather tepid statement, STP project manager Chris Dixon said, "Resuming tunneling will take longer than any of us would have liked, but making these repairs is a significant engineering challenge that must be done safely."

And in an even more tepid statement, WSDOT tunnel project manager Todd Trepanier added, "We are disappointed by this delay, but we believe the new schedule is moving in the right direction. We’ll continue to work with STP in their efforts to resume tunneling."

Previously, Trepanier told PubliCola that he has "no way of knowing" how much the tunnel delay will ultimately cost (WSDOT maintains that STP, not WSDOT or, ultimately, the taxpayers, is on the hook for any cost overruns), and wouldn't speculate on whether the delay will ultimately result in a lawsuit.